[PATCH v6 5/5] drm/amdgpu: resize VRAM BAR for CPU access v2
Bjorn Helgaas
helgaas at kernel.org
Thu Jun 1 20:14:30 UTC 2017
[+cc ADMGPU, DRM folks]
On Tue, May 09, 2017 at 06:49:07PM +0200, Christian König wrote:
> From: Christian König <christian.koenig at amd.com>
>
> Try to resize BAR0 to let CPU access all of VRAM.
>
> v2: rebased, style cleanups, disable mem decode before resize,
> handle gmc_v9 as well, round size up to power of two.
>
> Signed-off-by: Christian König <christian.koenig at amd.com>
> ---
> drivers/gpu/drm/amd/amdgpu/amdgpu.h | 1 +
> drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 37 ++++++++++++++++++++++++++++++
> drivers/gpu/drm/amd/amdgpu/gmc_v7_0.c | 8 ++++---
> drivers/gpu/drm/amd/amdgpu/gmc_v8_0.c | 8 ++++---
> drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c | 10 ++++----
> 5 files changed, 54 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu.h b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
> index 5310781..d6f5286 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
> @@ -1884,6 +1884,7 @@ uint64_t amdgpu_ttm_tt_pte_flags(struct amdgpu_device *adev, struct ttm_tt *ttm,
> struct ttm_mem_reg *mem);
> void amdgpu_vram_location(struct amdgpu_device *adev, struct amdgpu_mc *mc, u64 base);
> void amdgpu_gtt_location(struct amdgpu_device *adev, struct amdgpu_mc *mc);
> +void amdgpu_resize_bar0(struct amdgpu_device *adev);
> void amdgpu_ttm_set_active_vram_size(struct amdgpu_device *adev, u64 size);
> int amdgpu_ttm_init(struct amdgpu_device *adev);
> void amdgpu_ttm_fini(struct amdgpu_device *adev);
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> index 2719c02..4e83a56 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> @@ -694,6 +694,43 @@ void amdgpu_gtt_location(struct amdgpu_device *adev, struct amdgpu_mc *mc)
> mc->gtt_size >> 20, mc->gtt_start, mc->gtt_end);
> }
>
> +/**
> + * amdgpu_resize_bar0 - try to resize BAR0
> + *
> + * @adev: amdgpu_device pointer
> + *
> + * Try to resize BAR0 to make all VRAM CPU accessible.
> + */
> +void amdgpu_resize_bar0(struct amdgpu_device *adev)
> +{
> + u64 space_needed = roundup_pow_of_two(adev->mc.real_vram_size);
> + u32 rbar_size = order_base_2(((space_needed >> 20) | 1)) -1;
> + u16 cmd;
> + int r;
> +
> + /* Free the doorbell mapping, it most likely needs to move as well */
> + amdgpu_doorbell_fini(adev);
> + pci_release_resource(adev->pdev, 2);
> +
> + /* Disable memory decoding while we change the BAR addresses and size */
> + pci_read_config_word(adev->pdev, PCI_COMMAND, &cmd);
> + pci_write_config_word(adev->pdev, PCI_COMMAND,
> + cmd & ~PCI_COMMAND_MEMORY);
> +
> + r = pci_resize_resource(adev->pdev, 0, rbar_size);
> + if (r == -ENOSPC)
> + DRM_INFO("Not enough PCI address space for a large BAR.");
> + else if (r && r != -ENOTSUPP)
> + DRM_ERROR("Problem resizing BAR0 (%d).", r);
> +
> + pci_write_config_word(adev->pdev, PCI_COMMAND, cmd);
> +
> + /* When the doorbell BAR isn't available we have no chance of
> + * using the device.
> + */
> + BUG_ON(amdgpu_doorbell_init(adev));
This amdgpu_doorbell_fini()/amdgpu_doorbell_init() thing doesn't look
right. amdgpu_device_init() only calls amdgpu_doorbell_init() for
"adev->asic_type >= CHIP_BONAIRE", but we call it unconditionally
here.
This is the call graph:
amdgpu_device_init
adev->rmmio_base = pci_resource_start(adev->pdev, 5) # 2 for < BONAIRE
adev->rmmio = ioremap(adev->rmmio_base, ...)
DRM_INFO("register mmio base: 0x%08X\n", (uint32_t)adev->rmmio_base)
if (adev->asic_type >= CHIP_BONAIRE) {
amdgpu_doorbell_init
adev->doorbell.base = pci_resource_start(adev->pdev, 2)
adev->doorbell.ptr = ioremap(adev->doorbell.base, ...)
}
amdgpu_init
gmc_v7_0_sw_init # gmc_v7_0_ip_funcs.sw_init
gmc_v7_0_mc_init
+ amdgpu_resize_bar0
+ amdgpu_doorbell_fini
+ pci_release_resource(adev->pdev, 2)
+ pci_resize_resource(adev->pdev, 0, size)
+ amdgpu_doorbell_init
adev->mc.aper_base = pci_resource_start(adev->pdev, 0)
If "asic_type < CHIP_BONAIRE", we ioremapped BAR 2 in
amdgpu_device_init(), then we released the resource here and never
updated the ioremap.
>From the PCI core perspective, it would be much cleaner to do the BAR
resize before the driver calls pci_enable_device(). If that could be
done, there would be no need for this sort of shutdown/reinit stuff
and we wouldn't have to worry about issues like these. The amdgpu
init path is pretty complicated, so I don't know whether this is
possible.
I would also like to simplify the driver usage model and get the
PCI_COMMAND_MEMORY twiddling into the PCI core instead of the driver.
Ideally, the driver would do something like this:
pci_resize_resource(adev->pdev, 0, rbar_size);
pci_enable_device(adev->pdev);
And the PCI core would be something along these lines:
int pci_resize_resource(dev, bar, size)
{
if (pci_is_enabled(dev))
return -EBUSY;
pci_disable_decoding(dev); # turn off MEM, IO decoding
pci_release_resources(dev); # (all of them)
err = pci_resize_bar(dev, bar, size); # change BAR size (only)
if (err)
return err;
pci_assign_resources(dev); # reassign all "dev" resources
return 0;
}
> +}
> +
> /*
> * GPU helpers function.
> */
> diff --git a/drivers/gpu/drm/amd/amdgpu/gmc_v7_0.c b/drivers/gpu/drm/amd/amdgpu/gmc_v7_0.c
> index a9083a1..ae71524 100644
> --- a/drivers/gpu/drm/amd/amdgpu/gmc_v7_0.c
> +++ b/drivers/gpu/drm/amd/amdgpu/gmc_v7_0.c
> @@ -372,13 +372,15 @@ static int gmc_v7_0_mc_init(struct amdgpu_device *adev)
> }
> adev->mc.vram_width = numchan * chansize;
> }
> - /* Could aper size report 0 ? */
> - adev->mc.aper_base = pci_resource_start(adev->pdev, 0);
> - adev->mc.aper_size = pci_resource_len(adev->pdev, 0);
> /* size in MB on si */
> adev->mc.mc_vram_size = RREG32(mmCONFIG_MEMSIZE) * 1024ULL * 1024ULL;
> adev->mc.real_vram_size = RREG32(mmCONFIG_MEMSIZE) * 1024ULL * 1024ULL;
>
> + if (!(adev->flags & AMD_IS_APU))
> + amdgpu_resize_bar0(adev);
> + adev->mc.aper_base = pci_resource_start(adev->pdev, 0);
> + adev->mc.aper_size = pci_resource_len(adev->pdev, 0);
> +
> #ifdef CONFIG_X86_64
> if (adev->flags & AMD_IS_APU) {
> adev->mc.aper_base = ((u64)RREG32(mmMC_VM_FB_OFFSET)) << 22;
> diff --git a/drivers/gpu/drm/amd/amdgpu/gmc_v8_0.c b/drivers/gpu/drm/amd/amdgpu/gmc_v8_0.c
> index 4ac9978..1655de2 100644
> --- a/drivers/gpu/drm/amd/amdgpu/gmc_v8_0.c
> +++ b/drivers/gpu/drm/amd/amdgpu/gmc_v8_0.c
> @@ -534,13 +534,15 @@ static int gmc_v8_0_mc_init(struct amdgpu_device *adev)
> }
> adev->mc.vram_width = numchan * chansize;
> }
> - /* Could aper size report 0 ? */
> - adev->mc.aper_base = pci_resource_start(adev->pdev, 0);
> - adev->mc.aper_size = pci_resource_len(adev->pdev, 0);
> /* size in MB on si */
> adev->mc.mc_vram_size = RREG32(mmCONFIG_MEMSIZE) * 1024ULL * 1024ULL;
> adev->mc.real_vram_size = RREG32(mmCONFIG_MEMSIZE) * 1024ULL * 1024ULL;
>
> + if (!(adev->flags & AMD_IS_APU))
> + amdgpu_resize_bar0(adev);
> + adev->mc.aper_base = pci_resource_start(adev->pdev, 0);
> + adev->mc.aper_size = pci_resource_len(adev->pdev, 0);
> +
> #ifdef CONFIG_X86_64
> if (adev->flags & AMD_IS_APU) {
> adev->mc.aper_base = ((u64)RREG32(mmMC_VM_FB_OFFSET)) << 22;
> diff --git a/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c b/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c
> index b9f11fa..d65728a 100644
> --- a/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c
> +++ b/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c
> @@ -469,16 +469,18 @@ static int gmc_v9_0_mc_init(struct amdgpu_device *adev)
> }
> adev->mc.vram_width = numchan * chansize;
>
> - /* Could aper size report 0 ? */
> - adev->mc.aper_base = pci_resource_start(adev->pdev, 0);
> - adev->mc.aper_size = pci_resource_len(adev->pdev, 0);
> /* size in MB on si */
> adev->mc.mc_vram_size =
> nbio_v6_1_get_memsize(adev) * 1024ULL * 1024ULL;
> adev->mc.real_vram_size = adev->mc.mc_vram_size;
> - adev->mc.visible_vram_size = adev->mc.aper_size;
> +
> + if (!(adev->flags & AMD_IS_APU))
> + amdgpu_resize_bar0(adev);
> + adev->mc.aper_base = pci_resource_start(adev->pdev, 0);
> + adev->mc.aper_size = pci_resource_len(adev->pdev, 0);
>
> /* In case the PCI BAR is larger than the actual amount of vram */
> + adev->mc.visible_vram_size = adev->mc.aper_size;
> if (adev->mc.visible_vram_size > adev->mc.real_vram_size)
> adev->mc.visible_vram_size = adev->mc.real_vram_size;
>
> --
> 2.7.4
>
More information about the dri-devel
mailing list